Optimized solution

src/Year_2015/P6.py

@@ -32,8 +32,6 @@ from collections import defaultdict
 with open("files/P6.txt") as f:
     instructions = [line for line in f.read().strip().split("\n")]
 
-# print(instructions)
-
 
 def get_coordinates(s: str) -> tuple[str, int, int, int, int]:
     if s.startswith(("turn off", "turn on")):
@@ -54,39 +52,38 @@ def apply_action(
     action: str,
     coords: list[int],
     grid: dict[tuple[int, int], int],
-) -> dict[tuple[int, int], int]:
+) -> None:
+    x_start, y_start, x_end, y_end = coords
+
     if action == "off":
-        for x in range(coords[0], coords[2] + 1):
+        for x in range(x_start, x_end + 1):
-            for y in range(coords[1], coords[3] + 1):
+            for y in range(y_start, y_end + 1):
                 grid[x, y] = 0
-        return grid
+        return
-    elif action == "on":
+
-        for x in range(coords[0], coords[2] + 1):
+    if action == "on":
-            for y in range(coords[1], coords[3] + 1):
+        for x in range(x_start, x_end + 1):
+            for y in range(y_start, y_end + 1):
                 grid[x, y] = 1
-        return grid
+        return
-    elif action == "toggle":
+
-        for x in range(coords[0], coords[2] + 1):
+    # action == "toggle"
-            for y in range(coords[1], coords[3] + 1):
+    for x in range(x_start, x_end + 1):
-                if grid[x, y] == 1:
+        for y in range(y_start, y_end + 1):
-                    grid[x, y] = 0
+            grid[x, y] ^= 1
-                elif grid[x, y] == 0:
-                    grid[x, y] = 1
-        return grid
 
 
 def part_1():
-    # Initially, all lights are off("0")
+    # Initially, all lights are at brightness 0 (implicit via defaultdict(int))
-    grid = defaultdict(int)
+    grid: defaultdict[tuple[int, int], int] = defaultdict(int)
-    for x in range(1000):
-        for y in range(1000):
-            grid[x, y] = 0
 
     for instruction in instructions:
         action, *coords = get_coordinates(instruction)
-        grid = apply_action(action, coords, grid)
+        # in-place mutation of grid
+        apply_action(action, coords, grid)
+
+    lit = sum(grid.values())
 
-    lit = sum(1 for value in grid.values() if value == 1)
     print(f"There are {lit} ligths lit")
 
 
@@ -121,39 +118,37 @@ def apply_action_(
     action: str,
     coords: list[int],
     grid: dict[tuple[int, int], int],
-) -> dict[tuple[int, int], int]:
+) -> None:
+    x_start, y_start, x_end, y_end = coords
+
     if action == "off":
-        for x in range(coords[0], coords[2] + 1):
+        for x in range(x_start, x_end + 1):
-            for y in range(coords[1], coords[3] + 1):
+            for y in range(y_start, y_end + 1):
-                if grid[x, y] != 0:
+                grid[x, y] = max(grid[x, y] - 1, 0)
-                    grid[x, y] -= 1
+        return
-                else:
+
-                    grid[x, y] = 0
+    if action == "on":
-        return grid
+        for x in range(x_start, x_end + 1):
-    elif action == "on":
+            for y in range(y_start, y_end + 1):
-        for x in range(coords[0], coords[2] + 1):
-            for y in range(coords[1], coords[3] + 1):
                 grid[x, y] += 1
-        return grid
+        return
-    elif action == "toggle":
+
-        for x in range(coords[0], coords[2] + 1):
+    # action == "toggle"
-            for y in range(coords[1], coords[3] + 1):
+    for x in range(x_start, x_end + 1):
-                grid[x, y] += 2
+        for y in range(y_start, y_end + 1):
-        return grid
+            grid[x, y] += 2
 
 
 def part_2():
-    # Initially, all lights are off("0")
+    # Initially, all lights are at brightness 0 (implicit via defaultdict(int))
-    grid = defaultdict(int)
+    grid: defaultdict[tuple[int, int], int] = defaultdict(int)
-    for x in range(1000):
-        for y in range(1000):
-            grid[x, y] = 0
 
     for instruction in instructions:
         action, *coords = get_coordinates(instruction)
-        grid = apply_action_(action, coords, grid)
+        # in-place mutation of grid
+        apply_action_(action, coords, grid)
 
-    brightness = sum(value for value in grid.values())
+    brightness = sum(grid.values())
     print(f"The total brightness is {brightness}")